1. Field of the Invention
This invention relates to magnetic recording mediums such as, for example, magnetic disks having a thin metallic recording layer on the surface thereof.
2. Description of the Prior Art
Recent advances in the magnetic recording and reproducing apparatus are remarkable. These advances require high performance of magnetic recording mediums adapted for use in magnetic recording and reproducing apparatus. In order to meet these requirements, there have been proposed a number of magnetic recording mediums comprising thin metallic recording layers without use of any binder resins. This type of magnetic recording medium is ordinarily made by depositing under vacuum or sputtering ferromagnetic metal materials such as Co, Co-Ni alloys, Co-Cr alloys and the like, or non-magnetic supports such as sheets of polyethylene terephthalate, polyimides and the like.
However, although the magnetic material is packed in high density because no binder resins are present in the thin metallic layer, the magnetic layer shows a high frictional resistance when travelled on contact with hard magnetic heads, drums, guides and the like. This will cause the magnetic thin layer to be damaged. In an extreme case, the magnetic thin layer may partially come off. In addition, the magnetic layer is exposed, so that it tends to corrode on the surface thereof.